1. Field of the Invention
The invention relates to a local communication bus system comprising a single-channel control bus connected to a plurality of user terminal devices that are pairwise interconnected by respective signal interconnections. The system also includes at least one plural-interconnected switchbox means, and is able to establish a signal path between an initiating or source terminal and a destination terminal.
2. Description of the Related Art
A communication system having a single-channel control bus has been described in U.S. Pat. No. 4,429,884, herein incorporated by reference. Such a control bus is particularly suited for transfer of control signals between various user terminal for consumer entertainment, devices for executing household chores, and for producing various maintenance and management control signals in a domestic environment. In addition to the control bus, the various devices are pairwise interconnected by signal interconnections. Herein, pairwise means that either exactly two are interconnected, or that one particular device operates as signal source, whereas the others function exclusively as signal destinations. An example would be one audio amplifier that can selectively power either one of two (or more) loudspeaker boxes. The signals may be analog or digital and may relate to audio or video information or other. Certain devices, although attached to the control bus, need not be interconnected to such signal interconnection inasmuch as they have little or no signal handling facilities, such as switches, sensors etcetera. For these devices, the control bus would provide a data path of sufficient transport capability. Particular properties of such system are the low level of data processing facilities of many of the interconnected devices, and also the frequent configuration changes encountered inasmuch as many devices are portable and liable to plugging and unplugging in various physical attachment points of the control bus. In typical circumstances, such control bus could be wired to all rooms of a house or appartment and in each wired room have one or more wall-mounted plugs. Of course simpler configurations would also do. The devices often have only a single signal interconnection; anyway, the switchbox means have at least two such signal interconnections, typical values are four to six.